The trojan horse puzzle

[Arpad Rusz]

The author of this puzzle seems to be GM Surya Sekhar Ganguly,‏ I just proposed a correction.

[peter]

Thanks again, Arpad

[Paloma]

[Event "?"]
[Site "?"]
[Date "2017.09.26"]
[Round "?"]
[White "Trojan horse puzzle"]
[Black "by Surya Sekhar Ganguly"]
[Result "1-0"]
[Annotator "?"]
[SetUp "1"]
[FEN "3k4/8/7p/2p1p1pP/1pPpPpP1/1P1P1P2/N7/2K5 w - - 0 1"]
[PlyCount "52"]
[EventDate "2017.09.26"]

{all of the five Kingmoves are mate in 46} 1. Kb2
Kc8 2. Nc1 $1 {45#} Kb7 3. Ne2 {44#} Kc7 4. Ng1 Kd7 5. Nh3 $1 {42#} Ke7 6. Nf2
Kd6 7. Nd1 {40#} Kc6 8. Ka2 $2 {41#} (8. Kc1 $1 {39#}) 8... Kb6 $2 (8... Kd6 $1
9. Nb2 {39#} Kc6 10. Na4 Kd6 $1 11. Nb6 {37#} Ke7 12. Nd5+ {36#}) (8... Kc7 $3
9. Kb2 {40#} Kc6 10. Kc2 Kd7 11. Nb2 Ke7 (11... Kd6 $1 12. Na4 $5 Kc6) 12. Na4
Kd6) 9. Nb2 $2 {39#!} (9. Nf2 $1 {24#!} Kc6 10. Nh3 Kd7 11. Nxg5 $1 Ke7 12. Nh3
Kf6 13. Kb1 {20#} Ke6 14. Nxf4+ exf4 15. Kc1 Kf6 16. Kd2 Kg7 17. e5 {16#}) 9...
Kc6 10. Na4 $1 {38#} Kd6 $1 11. Nb6 $1 Ke6 12. Nd5 {36#} Kf7 $1 (12... Kd6 $2
13. Nf6 Ke6 14. Ng8) 13. Nc7 Ke7 $1 14. Nb5 {34#} Kd7 15. Na3 Kd6 (15... bxa3
16. Kxa3 {21#} Kc6 17. b4 cxb4+ 18. Kxb4 Kb6 19. c5+ Kc6 20. Kc4 Kc7 21. Kd5)
16. Nc2 {32#} Ke6 17. Ne1 {31#} (17. Kb2 {31#}) (17. Kb1 {31#}) 17... Kf6 18.
Ng2 (18. Kb2 {30#} Kg7 19. Kc1 Kf6 20. Kd1 Kf7 21. Ke2 {27#} Ke7 22. Kf2 Kf7
23. Kg2 Kf6 24. Kh3 Kf7 25. Ng2 Kg8 26. Nh4 gxh4 27. Kxh4 Kg7 28. g5 Kh7 29.
Kg4 hxg5 30. Kxg5 Kg7 31. Kf5 Kh6 32. Kxe5 Kxh5 33. Kxf4 Kg6 34. e5 Kg7 35. Kf5
Kf7 36. e6+ Kg7 37. Kg5 Kg8 38. Kf6 Kf8 39. e7+ Ke8 40. f4 Kd7 41. Kf7 Kc7 42.
e8=Q Kb7 43. Qb5+ Ka7 44. Ke6 Ka8 45. Kd6 Ka7 46. Kc6 Ka8 47. Qb7#) 18... Ke6
19. Kb2 Kf6 20. Kc2 Ke6 21. Kd2 Kf6 22. Ke2 Ke6 23. Kf2 {26#} Kf6 24. Kg1 Ke6
25. Kh2 Kf7 26. Kh3 {23#} Kf6 (26... Ke6 27. Nh4 gxh4 (27... Kf6 $2 28. Nf5 {
16#}) 28. Kxh4 {21#} Kf6 29. g5+ hxg5+ 30. Kg4 Kf7 (30... Kg7 31. Kxg5 {17#}
Kh7 32. h6 {16#}) 31. Kxg5 {18#} Kg7 32. Kf5 Kh6 33. Kxe5 Kxh5 34. Kxf4 {15#})
1-0

[Spliffjiffer]

as i thought

[Vinvin]

It seems that both 1.Kd2 and 1.Kb1 are equally good keys so I have corrected the study by modifying the position a bit:

http://ruszchessstudies.blogspot.hu/201 ... ess-3.html

Code: Select all

[Event "Internet (www.twitter.com)"]
[Site "?"]
[Date "2017.??.??"]
[Round "?"]
[White "Surya Sekhar Ganguly"]
[Black "(Fortress 3)"]
[Result "1-0"]
[EventDate "2017.??.??"]
[Annotator "correction by Rusz"]
[SetUp "1"]
[PlyCount "37"]
[FEN "7k/8/7p/2p1p1pP/1pPpPpP1/1P1P1P2/4K3/2N5 w - - 0 1"]

1.Kd2 $1 
    ( 1.Na2 $6 Kg7 
        ( 1...Kg8 )
    2.Nxb4 $2 cxb4 $11 )
1...Kg7 2.Ne2 Kf7 3.Ng1 Kf6 4.Nh3 Ke6 5.Nf2 
    ( 5.Nxg5+ $2 hxg5 $11 )
5...Kf6 6.Nd1 $1 
    {This move explains why we have not chosen 1.Kd1?!}
6...Ke6 7.Nb2 Kd6 8.Na4 Kc6 9.Kc1 $1 
    {Another precise move which puts black into zugzwang.}
9...Kd6 10.Nb6 Ke7 11.Nd5+ 
    ( {minor dual} 11.Nc8+ Ke6 12.Na7 Kd7 13.Nb5 )
11...Ke6 12.Nc7+ Kd7 13.Nb5 Kc6 14.Na3 $1 
    {Preparing this sacrifice was the reason of moving the white king to 
    the c-file.}
14...Kd6 15.Nc2 $1 
    {This move explains why we have not chosen 9.Kc2?!}
15...Ke6 16.Ne1 Kf6 17.Ng2 Ke6 18.Kd1 
    ( 18.Kd2 )
18...Kf6 19.Nh4 $1 1-0